Doping Efficiency of N-Type a-Si:H Doped with a Liquid Organic Source

1993 ◽  
Vol 297 ◽  
Author(s):  
K. Gaughan ◽  
ZHAOHUI Lin ◽  
J.M. Viner ◽  
P.C. Taylor ◽  
P.C. Mathur
Keyword(s):  
Activation Energy ◽  
Chemical Vapor Deposition ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Band Tail ◽  
Optical Gap ◽  
Heavily Doped ◽  
Pl Intensity

N-type amorphous silicon films were grown using a mixture of silane and tertiarybutylphosphine (TBP-C4H11P) vapor in a plasma enhanced chemical vapor deposition system. The concentration of TBP in silane was varied from 0 to 3% by volume. As expected, at low doping levels, the photoluminescence (PL) intensity associated with both the band-tail recombination (peak at 1.3 eV) and deep-defect recombination (peak at 0.8 eV) decreased as the impurity concentration increased, but for TBP concentrations > 0.1% the PL intensity increased again. For moderate doping levels the activation energy for conductivity leveled off at ∼ 0.2 eV. For concentrations of TBP > 0.1% the activation energy for dark conductivity increased. A shift in the optical gap was observed for the highest impurity concentrations due to the incorporation of carbon from the TBP. These results are interpreted as a pronounced decrease in the doping efficiency for heavily doped films (> 0.1%) perhaps influenced by the increased carbon concentration.

Effect of Ge Incorporation on Hydrogenated Amorphous Silicon Germanium Thin Films Prepared by Plasma Enhanced Chemical Vapor Deposition

2012 ◽  
Vol 569 ◽  
pp. 27-30
Author(s):  
Bao Jun Yan ◽  
Lei Zhao ◽  
Ben Ding Zhao ◽  
Jing Wei Chen ◽  
Hong Wei Diao ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Silicon Germanium ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Amorphous Silicon Germanium ◽  
Hydrogenated Amorphous

Hydrogenated amorphous silicon germanium thin films (a-SiGe:H) were prepared via plasma enhanced chemical vapor deposition (PECVD). By adjusting the flow rate of GeH4, a-SiGe:H thin films with narrow bandgap (Eg) were fabricated with high Ge incorporation. It was found that although narrow Eg was obtained, high Ge incorporation resulted in a great reduction of the thin film photosensitivity. This degradation was attributed to the increase of polysilane-(SiH2)n, which indicated a loose and disordered microstructure, in the films by systematically investigating the optical, optoelectronic and microstructure properties of the prepared a-SiGe:H thin films via transmission, photo/dark conductivity, Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR) measurements. Such investigation provided a helpful guide for further preparing narrow Eg a-SiGe:H materials with good optoelectronic properties.

Intrinsic microcrystalline silicon by postgrowth anneals

2001 ◽  
Vol 16 (6) ◽  
pp. 1531-1534 ◽  
Author(s):  
Jong-Hwan Yoon
Keyword(s):  
Activation Energy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Dark Conductivity ◽  
Microcrystalline Silicon ◽  
Conductivity Activation Energy ◽  
High Hydrogen ◽  
Constant Rate ◽  
Annealing Cycle

Hydrogenated microcrystalline silicon (μc-Si:H) grown by a conventional plasma-enhanced chemical vapor deposition from high hydrogen-diluted silane was annealed by increasing the temperature from 25 to 450 °C at a constant rate of 12 °C/min (one annealing cycle). Dark-conductivity activation energy gradually increases with increasing the number of annealing cycle to a saturation value of about 0.6 eV, observed in truly intrinsic μc-Si:H films. For the saturated state, the dark conductivity of the order of 10−8 S/cm was obtained. Little or no change in the oxygen content was observed after the annealing.

Deposition and Crystallisation Behaviour of Amorphous Silicon Thin Films Obtained by Pyrolysis of Disilane Gas at Very Low Pressure

1994 ◽  
Vol 345 ◽  
Author(s):  
T. Kretz ◽  
D. Pribat ◽  
P. Legagneux ◽  
F. Plais ◽  
O. Huet ◽  
...  
Keyword(s):  
Activation Energy ◽  
Growth Rate ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Electrical Conductance ◽  
Chemical Vapor ◽  
Crystalline Fraction ◽  
Silicon Thin Films ◽  
Crystallisation Behaviour

AbstractHigh purity amorphous silicon layers were obtained by ultrahigh vacuum (millitorr range) chemical vapor deposition (UHVCVD) from disilane gas. The crystalline fraction of the films was monitored by in situ electrical conductance measurements performed during isothermal annealings. The experimental conductance curves were fitted with an analytical expression, from which the characteristic crystallisation time, tc, was extracted. Using the activation energy for the growth rate extracted from our previous work, we were able to determine the activation energy for the nucleation rate for the analysed-films. For the films including small crystallites we have obtained En ∼ 2.8 eV, compared to En ∼ 3.7 eV for the completely amorphous ones.

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